Container seaming machine



m 30, 1944. w. L-HAWK m 2,349,865

CONTAINER SE-AMING MACHINE Filed Jan. 13, 1942 5 Sheets-Sheet l INVNT2R5 lgafsa rv L aw x u 7 BY l/e we/li/n M Evans INVENTORS Wa/son Z.Hawk Max 1 00/ BY Z/ewel/yrv MIL 0H5 w L. HAWK EI'AL ,86

CONTAINER SEAMING MACHINE I Filfid Jim. 13, 1942 5 Sheets-Sheet 2 May30, 1944. w. I... HAWK ETAL CONTAINER SEAMING MACHINE Filed Jan. 13,1942 5 Sheets-Sheet 3 HL H .I.

May 30, 1944. w, L, HAWK 2,349,865 I CONTAINER SEAMiNG M ACHIiiE ,FiledJan. 13, 1942 5 Sheetg-Sheet 4 y 30, 1944- w. L. HAWK EIAL 2,349,865

CONTAINER SEAMING MACHINE Filed Jan. 13, 1942 5 Sheets-She et 5 INVETOR5 wa/son Z. $44k Max flau/ y ZZ ewe/(yr? M [1/0/75 the presentinvention with a Patented May 30, 1944 2,843,865 CONTAINER SEAMINGMACHINE Paul, and Llewellyn W.

Watson L. Hawk, Max

Evans, Stockton,

Calih, assignors to Rhcem Manufacturing Company, Richmond, Calif, acorporation of California Application January 13, 1942, Serial No.426,608

10 Claims. The invention relates to welding machines and moreparticularly to such machines as may be adapted for seaming theperiphery of a container.

An object of the present invention is to provide a welding machine ofthe character described which is adapted for seaming the peripheryof apolygonal container and which is operative to move the entire polygonalperiphery of the container past a welding head at a constant linealspeed and spacing with respect to such head.

Another object of the invention is to provide a container seamingmachine of the character described having an improved container grippingand centering mechanism which is automatic in its operation to permit aneasy and rapid insertion and removal of the container and which willinsure a proper positioning of the container in the machine at all timesduring the seaming process. v

The invention possesses other objects and features of advantage, some ofwhich, with thef 'foregoing, will be set forth in the followingdescription of the preferred form of the invention which is illustratedin the drawings accompanying and forming part of the specification. Itis to be understood, however, that variations in the showing made by thesaid drawings and description may be adopted within the scope of theinvention as set forth in the claims.

Referring to said drawings:

Figure 1 is a front elevation of a container seaming machine constructedin accordance with part of the supporting frame shown in section.

Figure 2.is a plan sectional view of the machine taken substantially onthe plane of line 2 --2-of Figure 1.

Figure 3 is a vertical cross sectional view of the machine takensubstantially on the plane of line 3-3 of Figure 1.

Figure 4 is an end view of the machine.

Figure 5 is an enlarged fragmentary longitudinal vertical sectional viewof thecontainer'holding mechanism and attendant structure.

Figure 6 is a cross sectional view taken sulntlm tiallyon the plane ofline 6-6 of Figure 5,-showing one of the pressure plates infrontelevation.

Figure 7 is an enlarged fragmentary vertical sectional view showing oneof. the fastening detent members and associated structure, alsoseen inFigure 5.

Figures 8 to 16 inclusive area series ofdiagrammatic representationsshowing the progressive stages of movement of the pinion and ring gearand supporting structure for the latter, forming part of the presentmachine, in effecting a full peripheral movement of the container to beseamed.

Figure 17 is an enlarged fragmentary side elevation of a part of thering gear.

, The machine as depicted in the accompanying drawings consistsbrieflyof a pair of coaxial opposed rotatable head members which aremounted for universal movement in planes at right angles to their axisof rotation and which are adapted to grip a polygonal container havingstraight sides and rounded corners in endwise relation therebetween, incombination with an internal ring gear having a polygonal formconforming to the polygonal periphery of the container, and secured toat least one of the head members in coaxial relation thereto, and adrive pinion having a fixed axis of rotation and enmeshed with the ringgear and having a pitch radius equal to the radius of curvature of therounded corners of the ring gear, whereby the pinion will effect arectilinear movement of the ring gear and head members when engaged withthe straight sides of the ring gear and will effect a rotation of theheads and ring gear about the axis of the pinion when the pinion isengaged with the corners of the ring gear.

The machine is assembled upon a support 2| comprising essentially acubical frame including end frames 22 and 23 and longitudinallyextending top and bottom members 24 and 26. Mounted in opposed coaxialrelation within the supporting frame are a pair of head members 21 and28 which are adapted to grip a polygonal container 29 in endwise coaxialrelation therebetween. These head members are provided with axiallylongitudinally extending shafts 3| and 32 which are journaled forrotation in the upper ends of a yoke frame 33 which is in turn providedwith longitudinally spaced depending arms 35 which are pivoted at theirlower ends to the ends 3-! and 38 of a pair of counterbalancing levers39 and ll Journaled intermediate their length on a longitudinallyextending shaft 42 carried between the end frames 22 and 23. Weights 43and 44 are positioned at the opposite ends 46 and H of the levers so asto urge the upward positioning of the yoke frame 33 and the head members21 and 28. In this manner the head members are permitted a universalmovement, that is vertically and horizontally in planes at right anglesto the longitudinal axis of rotation of these head members. Preferablythe yoke frame. is supported against endwise displacement by means ofend abutment members 48 and toward the other so as to clamp the ends ofthe container 29 therebetween. Such means is in the adjacent platesll-63 and to swing outwardly and engage and lock with the container endflange 83-84. Thus upon initially positioning the container on guides1d, 16, ll, 18, and opening the control valve 68, head member 28 movesto the left as illustrated in Figure to clampthe container ends and ,inso. doing compre'ss'esgth head plates 69- 1|andsfi2-63 together againstthe resilience of springs 13, which action in turn rocks the dogs 82through the container engaging plates IL-B3 to forcibly engage thepresent case adapted to be pneumaticallymp erated and as here embodied,in head member 28. As will be seen from Figure 5,.this head mem- Y berincludes a casing memberj'r held by the yoke; frame against longitudinalmovement and formed .5 with an axial recess 58 thereindeflning apneumatic cylinder opening axiallytowa'rd the 'oppo and lock" in placethe end flanges of the container. Upon release of the pressure in thefluid cylind e r,58 and discharge of compressed fluid therefromthrodghmdischarge port (not shown) in the valve, the headmember 28 isretracted to the right, as viewed in Figure 5, by means of com-'pressionsprings98, see Figure 7, which are site head member H. A pistonBI is mountedrior axial reciprocation in the cylinder 53 and hassecuredto the forward side thereof a backing plate 62 which in "turn supports,a relatively'movable container end engaging 'plate' 63. Air or otheroperating fluid is supplied the cylinder 58 from the base end thereof bymeans or a passage extending axially through the shaft. 32" to which thecasing member 5] is fixed and which'is' 'operatively connected byafitting 66 to a fluid supply conduit 61 leading to a control valve '6B,"see'Fig ures 2 and 4, which is'connected between 'asource reservoir(not shown) and the cylinder 58'. Thus by opening of the control valve68, the head member 28 is displaced to the left, as'viewed in Figure 5,to thereby efiect a clampingoi a con}v tainer 29 placed between the headm'einbers.

The opposite head member 2.! is constructed similar to the head member28 but withoutthe pneumatic actuatorv and is composed of a backing plate69 fixed for rotation with shaft 3|, anda forwardly positioned, endwisedisplaceable, container engaging plate 'IL- Stripperbolts12 connect thetwo plates 62-63 and Billlicit the head members 2! and 28 for limitingthe separation of the plates and such separation is normally urgedby aplurality of springs 13 mounted between the plates. As aforementioned,the present machine has been designed for handling containers ofpolygonal form, that is one having straight sides and rounded cornerswhen viewed in end elevation or transverse section. An initial sup portfor the container is provided by right answlarly arranged guide members14 and i6, and l! and 58 mounted on the container engaging faces 79 andBI of head plates II and 63 adapted to provide a base support anddepthwise stop for the opposite ends of the containers. In addition tothe endwise clamping of the container between the head members,transverselocking means'is provided here in the form of a plurality ofdogs or detents 82 which are automatically projected from the containerengaging faces 19 and BI of the heads to engage andlock with the endwiseextending flanges 83 and-84 bounding the head ends 66 and 81 of thecontainer. These dog are mounted in openings 88 and 89 in the backingplates 69 and 6| and arepivoted intermediate their lengths to the platesalong axes parallel to the plane of the plates and are of bell crankform having one end 9| extending from the pivot in the plane of theplate and adapted for engagement with and displacement by the adjacentplates Ii-63, and anopposite end 92iextending at right angles to theplane ofthe plate and positioned to project through openings. 93 and '94in mounted-oh bolts 9'! connecting plate 62 and the casing member 51,This separation of the head members is accompanied by a separation ofthe plates 69--"H and $2-33;'due to action of springs 73, and aretr'action'of the dog ends" 92 into the openings 93-94 and away fromthe plate faces l'9" 8|,- thus permitting sliding out of the container29 and insertion of a new container. Preferably; and ashereshown, thewalls of the openings 93- 94 arebeveled at the dogs 82 and the dogsrounded thereat so as to produce theretractive rocking of the dogsends'QZ into the openings 939 l upon separation of the plates.

V accordance with the present invention and as a principal featurthereof, means i provide'd for moving thehead. members and container'c1amped ther ebetween through a polygonal course pfjm'ovement exactlyconforming to the polygonal shapefof the container periphery, so asto'cause thefentire periphery of the container to pass a fixed point,such as a welding head, at a constant velocity and while maintaining aconstant spacing with respect to such point. The container'for 'whichthepresent machine has been designed is of; rectangular shape in crosssection having straight sides and rounded corners, although as will bepresently-more clearly understood, the machine may be readily adaptedfor use with any polygonal container or other obj ect' having roundedcorners. To'efiect such a movement, we mount on-at least one of the headmembers and preferably on both, and in coaxial relation "thereto, aninternal ring gear 98 which'is formed with a tooth 'pitch'line of apolygonal form exactly conforming to fthe-polygonal form of thecontainer peri'ph'ery; Thus the pitch radius of the corners I0 I,

")2, I03, I54 of the gear and the length of the straight'sides I06,IO'IQIOB, I09 thereof, see Figures Ste 17, are identical to the radiusof curvature and the length, respectively, of the corners 'andsides ofthe container periphery. 'As will be best seen from Figures 1 and 5, wemount one of such ring gears 98 in the head 21 by fastening thegear-at-theouter side of plate 69, asurrounding band I'I l being usedaround the gear and the periphery ofplate 69 to assist in holding themembers together; In-the opposite head 28,':an identical-ring gear-98isfastened to the outer side'of the-casing'member 51,- a-bahd H2 similarto band-.1 H being usedaround the ri-ng'gear and icasing member forassembly purposes.

The ring gears and the opposite head-members are driven inunison bymeans of pinions H3 enmeshed with the ring gears and mounted on driveshafts H4 extending longitudinally through the :endframes: 22 and-23 togear boxes Ii6,-'H1 mounted on supporting platforms l I-B'a'nd Mon theend frames 22 and 23. As will be seen from Figures 1 and 5, the pinionsH3 are positioned to engage the top portion of the ring gear, and aswill be seen from Figures 1 and 2, the pinion shafts H4 are mounted inlongitudinal coaxial alignment. In the present construction power fordriving the pinions is derived from an electric motor I2I mounted at thebase of the support and connected by belt I22 and pulleys I23- I24 to acounter-shaft I25 extending lengthwise of the support between the endframes. This latter shaft is in turn connected by belt I21 and pulleysI28 and I29 to a second counter-shaft I3I extending across the back ofthe machine between the end frames, see Figure 2, the several pulley andbelt connections being such as to effect a substantial reduction inspeed from the motor I2l to the counter-shaft Hi. The opposite ends ofshaft I3I are journaled in gear boxes I32 and I33 containing bevelpinions |34-I35 and I36- I31 for transmitting the drive at right anglesto shaft I3I by way of forwardly extending shafts I38 and I39 connectinggear boxes I32 and I33 to gear boxes H6 and H1, see Figure 2. A furtherreduction in speed is eifected in gear boxes H6 and I I! by the use ofworms MI and I42 on shafts I 38 and I 39 which engage worm gears I43 andI44 on shafts H4. Besides effecting a desirable reduction in speed, theworm gear drive in gear boxes H-I I1 afiords an even more importantfunction of serving as a unidirectional drive and effectively preventingthe ring gears, weighted by the structure connected thereto, fromdriving the pinions when the ring gears are in an imbalanced positionwith respect to the pinions. In other words in order to obtain aconstant lineal displacement of the ring gears and head, it is necessarythat the speed of rotation of the pinions which may be controlled,remain constant and any over-driving of the pinions by the ring gearwould interfere with this constant speed of rotation of the ring gearand entire drive mechanism. Thus the Worms HI and I42 operate not onlyto transmit a constant speed of movement to the worm gears I43 and I44,but in addition prevent such worm gears from transmitting motion to theworms to cause an acceleration when an imbalanced position of the ringgears and head assembly woul urge such acceleration.

In accordance with the present construction and as will be best seenfrom Figure 3, the pitch radius of the pinions I I3 is equal to theradius of curvature of the pitch circle in the corners of the ring gear,whereby a positive lock between the pinion and gear corners is effectedwhen these parts are enmeshed. As a result the pinion drive is effectiveto produce a constant rectilinear movement of the ring gears whenengaged with the straight sides IIlIi-I 89 thereof and to cause aconstant annular displacement of the ring gears about the axis of'thepinions when the pinions are engaged with the corners I ll I-l I14 ofthe ring gears. In either event since the peripheral peed of the pinionis constant .at all times, the peripheral speed of the ring gear islikewise constant.

In order to insure a proper rectilinear movement of the ring gears andheads secured thereto as such movement is imparted to the ring gears bythe pinions H3, we provide across the top of the ring gears a straightguide here in the form of a plurality of rollers I45, I41, I48, I49,I50, I5I, which engage the outer periphery I52 of the ring gear, or morespecifically the outer periphery of the bands II I and H2 which conformto the periphery of the ring gears. The peripheries of by a distanceapproximately equal to the thickness of the ring gear plus the bandIII-I I2, whereby the ring gear will be confined therebetween, and therollers are so arranged that the straight line guide provided therebyextends on opposite sides, depthwise, of the pinion I I3 whereby asupport is afforded the ring gears over approximately the full length ofthe sides thereof. Preferably and as here shown in Figure 3, one of theintermediate rollers I49 is located directly over the pinion H3. Withthe pinion rotating in a clockwise direction, with reference to thisfigure, the ring gear will be displaced rectilinearly to the right untilthe pinion H3 engages the left hand upper corner of the ring gear, whenthe latter will be rotated about the axis of the pinion to engage theadjacent side of the ring gear against the roller peripheries. In orderto obtain a guide support for the ring gears during rotative movementthereof at the corners, We preferably provide a flat plate guide I53between rollers I49 and I50 whereby a guide support can be obtainedclose to the periphery of roller I49 and pinion I I3 to support the ringgear during rotative movement. With further reference to Figure 3 and toFigures 8, 9 and 10, it will be noted that the ring gear in its courseof movement passes across the verticalcenter of the lower yoke framepivot whereby conditions of imbalance are present. This imbalancedcondition is counteracted by the combination of the straight guidesupport provided by rollers I46-I 5| and the constant upward urge on theyoke frame 33 provided by the counter-balancing levers 39.

In accordance with the foregoing it will be seen that in the operationof the device, the polygonal container or other object carried betweenthe heads, is caused to pass through a polygonal course of movementconforming to the periphery of the device and that with reference to thedrive pinions H3, such object is caused to pass a fixed point at aconstant lineal speed. In the present construction this operation istaken advantage of for welding the heads 86 and 8 1 of the container tothe side walls I54 of the container, and accordingly we position at theseams joining the heads and side Walls and in a longitudinally alignedplane with the pinions H3, a pair of welding heads I58 and I51. Thelatter are here supported on a longitudinally extending rod I58 which issupported over the head members by end brackets I59I6I depending fromthe rod I58 and secured to the end frames 22 and 23. Preferablyinsulation sleeves I62 and I63 slidably mounted on the rod I58 insulatethe welding heads from the rod. Flash guards I64 and I66 are desirablymounted across the top of the machine, as illustrated in Figures 1 and3, in covering relation to the heads 21 and 28 to shield the latteragainst weld splatter. These flash guards are desirably of sheet metalconstruction using non-ferrous metal such as copper, brass, bronze orthe like, so as to prevent sticking of weld metal thereto.

The complete cycle of operation of the ma- .chine is illustrated inFigures 8 to 16 0f the drawings. Starting with the representation inFigure 8 and assuming a clockwise direction of rollers I 46--I5I' arespaced from the pinion H3 rotation of, the pinion, it will be seen thatthe top straight side of the container corresponding to side I 86 of thering gear will be displaced rectilinearly across the welding head I56.To facilitate a description of these views which are more or lessdiagrammatic, the numbers of the gear sides and corners will be referredto as the equivalent sides of the container. The complete welding acrossside IDS is indicated with reference to Figure 9, where the-ring gear isdisplaced to the right to bring corner llll into engagement with thepinion. In the course of this operation the frame 33 indicated as abroken line, passes across the vertical center of its lower pivotalconnection to the counter-balancing levers 39, here alsodiagrammatically indicated. The engagement of the pinion with cornerIlll effects a rotation of the ring gear about the axis of the pinion tothe position illustrated in Figure 10, where the continuing rotation ofthe pinion passes side I09 across the point of the welding head. Figure11 shows the completion of welding along this side I09 and engagement ofthe pinion with corner I04; Continued rotation of the pinion causesrotation of the ring gear about the pinion axis to the positionindicated in Figure 12, where side I08 is brought up for traversingunder the welding head. Figure '13 shows the completion of welding alongside I08 and engagement of the pinion in corner I03. The subsequentrotation of the ring gearto rotate side I01 up to the welding head isshown in Figure 14 and the traversal of this side and engagement of thepinion with corner I02 is shown in Figure 15. Figure 16 shows therounding of corner I02 and the completing of the welding cycle. Uponcompletion of the welding cycle the drive is stopped and Valve 68operated to release the seamed container for removal from the machine,and a new container assembly is positioned in the machine for start of anew operation.

' Preferably in order to obtain a proper movement of the pinion teethinto and out of engagement with the corner teeth it! of the ring gear,see Figure 1'7, while providing a proper locking engagementtherebetween, we prefer to relieve the corner teeth I61 of the ringgear, as shown in Figure 17, to enable proper entry into enmeshedposition of the pinion teeth.

We claim:

1. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed, apair of rotatable head members mounted in axially spaced relation upon acommon axis of rotation and being supported for universal displacementin a plane at right angles to said axis, means for moving one of saidhead members toward the other for gripping said object therebetween, apolygonal internal rack gear mounted on one of said head members incoaxial relation thereto and having straight sides and rounded cornersconforming to the peripheral shape of said object, a plurality ofrollers having the peripheries theeof in a straight line adapted toengage and support the sides of said gear, a drive pinion enmeshed withsaid gear and located in alignment with said fixed point and having apitch radius equal to the radius of curvature of the corners of saidgear so as to drive said gear rectilinearly when engaged with thestraight sides thereof and to rotate said gear when engaged with thecorners thereof, and, means connected to said 'head members for holdingthe sides of said gear in engagement with I said rollers during periodsof engagement of said pinion with said sides.

2. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed, asupport, a polygonal internal ring gear rotatably carried by saidsupport for universal movement in a plane at right angles to the axisthereof, said. gear having straight sides and rounded cornersconformingto the peripheral shape of said object, ,a straight guide carried bysaid support and positioned for engagement with the straight sidesofsaid ring gear, means for securing said gear and object together inaligned position, a drive-pinionenmeshed with said gear and located inalignment with said fixed point and having a pitch radius equal to theradius of curvature ofthe corners of said gear, and means connected tosaid gear at approximately the center thereof and yield-ably urging saidgear toward said guide. a

3. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed, apair of rotatable head .members mounted in axially spaced relation upona common axis of rotation and being supported for universal displacementin a plane at right angles to said axis, means for moving one of saidhead members toward the other for gripping said object therebetween, apolygonal internal ring gear carried by each of said head memberscoaxially thereof, said gears having straight sides and rounded cornersaxially aligned with each other and conforming to the polygonal shape ofsaid object, drive pinions enmeshed with said gears and mounted in.axial alignment aligned with said fixed point, vsaid pinions having apitch radius equal to the radius of curvature of the corners of saidgear; means including a plurality of rollers spaced transversely of saidpoint and en- 'gageable with said gears and positioned to cooperate withsaid pinions for guiding the gears in a straight line when movingrectilinearly, and means for driving said pinions in synchronism at aconstant rate of speed.

4. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed, asupport, a drive pinion carried by said support,

'apolygonalinternal ring gear having straight sides an'd 'rounde'dcorners conforming to the peripheral shape of said polygonal object andmounted 'on' "said pinion,

a straight guide mounted over 'said-pinion a'nd spaced therefrom byapproximately the thickness of said ring gear for support of thestraightsides of said ring gear thereagainst, said pinion having a pitch radiusequal to the radius of curvature of the corners of said ring gearwhereby said pinion will displace the, sides of said ring gearrectilinearly 55 with .said sides and will rotate said gear about alongsaid guide when said pinion is enmeshed the axis of said pinion whensaid pinion is enmeshed with the corners of said gear, a universalsupport for said ring gear permitting said rectilinear and'rotative'movement aforesaid, means for yieldingly urging said ring gear towardssaid guide, and means for driving said pinion at a constant speedand'including a mechanism to preventover-drivingof said pinion by saidring gear.

5. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed,

a pair of rotatable head members mounted for coaxial rotation in.axially spaced relation, an internal ringgear carried by each of saidhead members coaxial therewith and having straight sides and roundedcorners conforming to the peripheral form of said object, pneumaticallyactu ated means connected to one of said head memhere for axiallyreciprocatingthe same for clamping said object between-said head membersin coaxial relation thereto for rotation of said object with said headmembers, and a drive pinion enmeshed with each .of said; gears andhaving a pitch radius equal to the radius of ourvature of the corners ofsaid gears whereby said pinion will drive said ring gearsand headmembers rectilinearly while engaged with the straight sides of saidgears and will rotate said gears and head members about the axes of saidpinions when said pinions are engaged with the corners of said ringgears, means to guide said gear in a straight line when movingrectilinearly, and means cooperating with said pinion for holding theside of the gear against said guide means during periods of engagementof said pinion with said sides.

6. In a machine of the character described for moving a polygonal objecthaving rounded corneds past a fixed point at a constant lineal speed, apair of rotatable head members mounted for coaxial rotation in axiallyspaced relation, an internal ring gear carried by each of said headmembers coaxial therewith and having straight sides and rounded cornersconforming to the peripheral form of said object, one of said headmembers being formed with a fluid cylinder extending axially thereof andopening toward the other head member, a piston mounted for reciprocationin said cylinder, a pressure plate carried by said piston and movabletherewith for clamping said object between said plate and said otherhead member for rotation of said object with said head members, and adrive pinion enmeshed with each of said gears and having a pitch radiusequal to the radius of curvature of the corners of said gears wherebysaid pinion will drive said ring gears and head members rectilinearlywhile engaged with the straight sides of said gears and will rotate saidgears and head members about the axes of said pinionswhen said pinionsare engaged with the corners of said ring gears, means to guide saidgear in a straight line when moving rectilinearly, and means coopcratingwith said pinion for holding the side of the gear against said guidemeans during periods of engagement of said pinions with said sides.

7. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed, asupport, a frame mounted for vertical movement on said support andpivoted at its base along a horizontal axis for horizontal and verticalmovement of the upper end thereof, head members rotatably carried at theupper end of said frame in spaced relation along a common axis ofrotation parallel to said first axis, meansfor moving one of said headmembers toward the other to clamp said object therebetween, a ring gearmounted coaxially on at least one of said head members and havingstraight sides and rounded corners conforming to the peripheral shape ofsaid object, a drive pinion carried by said support and enmeshed withsaid gear and having a pitch radius equal to the radius of curvature ofsaid gear corners, means to guide said gear in a straight line whenmoving rectilinearly, and means cooperating with said pinion for holdingthe side of the gear against said guide means during periods ofengagement of said pinion with said sides.

8. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed, asupport, a pair of drive pinions carried by said support in spacedrelation along a common horizontal axis, an internal ring gear hung uponeach of said pinions and having straight sides and mounted cornersconforming to the peripheral form of said object, said drive pinionshaving a pitch radius equal to the radius of curvature of said gearcorners, a head member secured to each of said ring gears, means fordisplacing one of said head members toward the other for clamping, saidobject therebetween in coaxial relation therewith, a horizontal guidecarried by said support and spaced over said pinion by a distanceapproximately equal to the thickness of said ring gear and adapted toengage the outer periphery of said ring gear, a yoke member journaled atits upper end to said head members along a common horizontal axisapproximately centrally of said ring gears, a lever pivoted intermediateits ends to said support adjacent the base thereof and pivoted adjacentone end to the lower end of said yoke member, and a weight mounted onthe opposite end of said lever for constantly urging the upwarddisplacement of said yoke and head members to maintain engagement of theouter peripheral sides of said ring gears with said guides.

9. In a machine of the character described for moving a polygonal objecthaving rounded corners past a fixed point at a constant lineal speed, asupport, a pair of drive pinions carried by said support in spacedrelation along a common horizontal axis, an internal ring gear hung uponeach of said pinions and having straight sides and rounded cornersconforming to the peripheral form of said object, said drive pinionshaving a pitch radius equal to the radius of curvature of said gearcorners, a head member secured to each of said ring gears, means fordisplacing one of said head members toward the other for clamping saidobject therebetween in coaxial relation therewith, a horizontal guidecarried by said support and spaced over said pinion by a distanceapproximately equal to the thickness of said ring gear and adapted toengage the outer periphery of said ring gear, a yoke member journaled atits upper end to said head members along a common horizontal axisapproximately centrally of said ring gears, a lever pivoted intermediateits ends to said support adjacent the base thereof and pivoted adjacentone end to the lower end of said yoke member, a weight mounted on theopposite end of said lever for constantly urging the upward displacementof said yoke and head members to maintain engagement of the outerperipheral sides of said ring gears with said guides, and a drivemechanism for each of said pinions in cluding a worm reduction gear toprevent overdriving of said pinions by said ring gears when the latterare in an out of balance position with respect thereto.

10. A welding machine for seaming the periphery of a container having apolygonal periphery in transverse section, comprising, a support, a pairof rotatable head members mounted on said support for coaxial rotationin axially spaced relation, means for supporting each of said headmembers for universal movement in a plane at right angles to the axis ofrotation thereof, means moving one of said head members toward the otherto grip said container in endwise relation therebetween, an internalring gear secured to each of said head members in coaxial relationtherewith and having straight sides and rounded corners conforming tothe peripheral shape of said container, a drive pinion carried by saidsupport and enmeshed with each of said ring gears and mounted in coaxialrelation with each other and having a pitch radius equal to the radiusof curvature of said gear corners whereby said pinions will drive saidhead members and said ring gears rectilinearly when said pinions areengaged with the straight sides of said ring gears and will rotate saidhead members and ring gears around the axes of said pinions when saidpinions are engaged with said gear corners, means to guide the ring gearin a straight line when moved rectilinearly, a welding head carried bysaid support in alignment with said pinions and in an operative relationto the periphery of said container, and flash guards carried by saidsupport in covering relation to said head members.

WATSON L. HAWK. MAX PAUL. LLEWELLYN W. EVANS.

